Override Base.getproperty for Gabor kernel

Author: sharanry

src/kernels/gabor.jl

@@ -1,3 +1,5 @@
+import Base.getproperty
+
 """
     GaborKernel(; ell::Real=1.0, p::Real=1.0)
 
@@ -8,14 +10,12 @@ Gabor kernel with length scale ell and period p. Given by
 
 """
 struct GaborKernel{T<:Real, K<:Kernel} <: BaseKernel
-    ell::T
-    p::T
     κ::K
     function GaborKernel(;ell=nothing, p=nothing)
         k = _gabor(ell=ell, p=p)
-        if ell==nothing ell=1.0 end
-        if p==nothing p=1.0 end
-        new{Union{typeof(ell),typeof(p)}, typeof(k)}(ell, p, k)
+        if ell == nothing ell=1.0 end
+        if p == nothing p=1.0 end
+        new{Union{typeof(ell),typeof(p)}, typeof(k)}(k)
     end
 end
 
@@ -33,6 +33,22 @@ function _gabor(; ell = nothing, p = nothing)
     end
 end
 
+function Base.getproperty(k::GaborKernel, v::Symbol)
+    if v == :κ 
+        return getfield(k, v)
+    elseif v == :ell && typeof(k.κ.kernels[1]) <: SqExponentialKernel
+        return 1.0
+    elseif v == :ell && typeof(k.κ.kernels[1]) <: TransformedKernel
+        return 1 ./ k.κ.kernels[1].transform.s[1]
+    elseif v == :p && typeof(k.κ.kernels[2]) <: CosineKernel
+        return 1.0
+    elseif v == :p && typeof(k.κ.kernels[2]) <: TransformedKernel
+        return 1 ./ k.κ.kernels[2].transform.s[1]
+    else
+        error("Invalid Property")
+    end
+end
+
 kappa(κ::GaborKernel, x, y) where {T<:Real} = kappa(κ.κ, x ,y)
 
 function kernelmatrix(

test/test_kernels.jl

@@ -69,7 +69,11 @@ x = rand()*2; v1 = rand(3); v2 = rand(3); id = IdentityTransform()
         end
     end
     @testset "Gabor" begin
-        k = GaborKernel(ell=abs(rand()), p=abs(rand()))
+        ell = abs(rand())
+        p = abs(rand())
+        k = GaborKernel(ell=ell, p=p)
+        @test k.ell == ell
+        @test k.p == p
         @test kappa(k,v1,v2) ≈ exp(-sqeuclidean(v1,v2) ./(k.ell.^2))*cospi(euclidean(v1,v2)./ k.p) atol=1e-5
         @test kappa(k,v1,v2) ≈ kappa(transform(SqExponentialKernel(), 1/k.ell),v1,v2)*kappa(transform(CosineKernel(), 1/k.p), v1,v2) atol=1e-5
     end